| /* |
| * Copyright (C) 2014 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.tools.lint.checks; |
| |
| import com.android.annotations.NonNull; |
| import com.android.annotations.Nullable; |
| import com.android.tools.lint.client.api.JavaParser; |
| import com.android.tools.lint.detector.api.Category; |
| import com.android.tools.lint.detector.api.Detector; |
| import com.android.tools.lint.detector.api.Implementation; |
| import com.android.tools.lint.detector.api.Issue; |
| import com.android.tools.lint.detector.api.JavaContext; |
| import com.android.tools.lint.detector.api.Scope; |
| import com.android.tools.lint.detector.api.Severity; |
| import com.android.tools.lint.detector.api.Speed; |
| import com.google.common.collect.Sets; |
| |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Set; |
| |
| import lombok.ast.AstVisitor; |
| import lombok.ast.Expression; |
| import lombok.ast.MethodInvocation; |
| import lombok.ast.Node; |
| import lombok.ast.StrictListAccessor; |
| import lombok.ast.StringLiteral; |
| |
| /** |
| * Ensures that Cipher.getInstance is not called with AES as the parameter. |
| */ |
| public class CipherGetInstanceDetector extends Detector implements Detector.JavaScanner { |
| public static final Issue ISSUE = Issue.create( |
| "GetInstance", //$NON-NLS-1$ |
| "Cipher.getInstance with ECB", |
| "`Cipher#getInstance` should not be called with ECB as the cipher mode or without " |
| + "setting the cipher mode because the default mode on android is ECB, which " |
| + "is insecure.", |
| Category.SECURITY, |
| 9, |
| Severity.WARNING, |
| new Implementation( |
| CipherGetInstanceDetector.class, |
| Scope.JAVA_FILE_SCOPE)); |
| |
| private static final String CIPHER = "javax.crypto.Cipher"; //$NON-NLS-1$ |
| private static final String GET_INSTANCE = "getInstance"; //$NON-NLS-1$ |
| private static final Set<String> ALGORITHM_ONLY = |
| Sets.newHashSet("AES", "DES", "DESede"); //$NON-NLS-1$ |
| private static final String ECB = "ECB"; //$NON-NLS-1$ |
| |
| @NonNull |
| @Override |
| public Speed getSpeed() { |
| return Speed.FAST; |
| } |
| |
| // ---- Implements JavaScanner ---- |
| |
| @Nullable |
| @Override |
| public List<String> getApplicableMethodNames() { |
| return Collections.singletonList(GET_INSTANCE); |
| } |
| |
| @Override |
| public void visitMethod(@NonNull JavaContext context, @Nullable AstVisitor visitor, |
| @NonNull MethodInvocation node) { |
| // Ignore if the method doesn't fit our description. |
| JavaParser.ResolvedNode resolved = context.resolve(node); |
| if (!(resolved instanceof JavaParser.ResolvedMethod)) { |
| return; |
| } |
| JavaParser.ResolvedMethod method = (JavaParser.ResolvedMethod) resolved; |
| if (!method.getContainingClass().isSubclassOf(CIPHER, false)) { |
| return; |
| } |
| StrictListAccessor<Expression, MethodInvocation> argumentList = node.astArguments(); |
| if (argumentList != null && argumentList.size() == 1) { |
| Expression expression = argumentList.first(); |
| if (expression instanceof StringLiteral) { |
| StringLiteral argument = (StringLiteral)expression; |
| String parameter = argument.astValue(); |
| checkParameter(context, node, argument, parameter, false); |
| } else { |
| JavaParser.ResolvedNode resolve = context.resolve(expression); |
| if (resolve instanceof JavaParser.ResolvedField) { |
| JavaParser.ResolvedField field = (JavaParser.ResolvedField) resolve; |
| Object value = field.getValue(); |
| if (value instanceof String) { |
| checkParameter(context, node, expression, (String)value, true); |
| } |
| } |
| } |
| } |
| } |
| |
| private static void checkParameter(@NonNull JavaContext context, |
| @NonNull MethodInvocation call, @NonNull Node node, @NonNull String value, |
| boolean includeValue) { |
| if (ALGORITHM_ONLY.contains(value)) { |
| String message = "`Cipher.getInstance` should not be called without setting the" |
| + " encryption mode and padding"; |
| context.report(ISSUE, call, context.getLocation(node), message); |
| } else if (value.contains(ECB)) { |
| String message = "ECB encryption mode should not be used"; |
| if (includeValue) { |
| message += " (was \"" + value + "\")"; |
| } |
| context.report(ISSUE, call, context.getLocation(node), message); |
| } |
| } |
| } |